<!DOCTYPE html>
<html>
    <head>
        <title>第一节课</title>
        <meta charset="utf-8">
    </head>
    <body>
        <h1 align="left">一级标题</h1>
        <h2 align="center">二级标题</h2>
        <h3 align="right">三级标题</h3>
        <h4>四级标题</h4>
        <h5>五级标题</h5>
        <h6>六级标题</h6>
        <ul>
            <li>项目列表</li>
            <li>圆点<li>
            <h1 align="center"><li>cq学姐今天骂人了吗<li><h1>
        </ul>
        <hr color="red" width="300px" size="20px" align="left" >
        <p>文本段落<p>
        <p>在不产生<br>新段落的情况下换行<br>width:长<br>size:宽</p>
    </body>
</html>